1. Field of the Invention
The present invention relates to a rotary brush floor polisher, and more particularly to a rotary brush floor polisher provided with a disk-like rotary brush or pad rotatably driven by an electric motor, the polisher being adapted to glide smoothly over a floor to polish and clean the floor by means of the brush or pad.
2. Description of the Prior Art
Heretofore, it has been known to provide a rotary brush floor polisher of the type shown in Japanese Utility Model Laid-Open No. 58-104171 having a construction as shown in FIGS. 11 and 12 in which: an upper disk member 1 is oppositely disposed from a lower disk member 2; a plurality of mounting bolts 3 are vertically fixed to a peripheral portion of an upper surface of the lower disk member 2 at equal angular intervals; a plurality of bolt holes 4 are vertically formed in a peripheral portion of the upper disk member 1 at positions corresponding to those of the mounting bolts 3 of the lower disk member 2, each of which bolts holes 4 is slightly larger in diameter than the mounting bolts 3 and receives a bushing 5 therein as shown in FIG. 12; and each of the mounting bolts 3 of the lower disk member 2 passes upward through a coil spring 7 having interposed between the upper disk member 1 and the lower disk member 2 and also passes through each of the bushings 5 having been mounted in the bolt holes 4 of the upper disk member 1, and is threadably connected with a nut 6 so that the upper disk member 1 is vertically movably connected with the lower disk member 2.
The above conventional rotary brush floor polisher is provided with a shock absorbing means for reducing vibrations of the rotary brush. However, the conventional floor polisher is not provided with a shock absorbing means for reducing vibrations of the electric motor, so that vibrations of the motor and the upper disk member 1 are directly transmitted to the hands of an operator holding the floor polisher through an operating handle of the polisher. In addition, the conventional floor polisher is too noisy in operation.
In the conventional floor polisher having the above construction, there is a fear that the mounting bolts 3 scrub the inner surfaces of the bushings 5, or a fear that the mounting bolts 3 excessively tilt in the bushings 5 to jam the coil springs 7 between the upper disk member 1 and the lower disk member 2, whereby the coil springs 7 are prevented from absorbing shocks produced in operation of the floor polisher.
In addition, when the mounting bolts 3 scrub the inner surfaces of the bushings 5 or excessively tilt in the bushings 5, a considerable noise is produced in operation of the floor polisher.
Further, in case that the floor polisher vibrates with large amplitude in operation, an upper end portion of each of the mounting bolts 3 excessively extends upward from the upper surface of the upper disk member 1 to make it impossible to realize a substantial reduction in size of the polisher.
Furthermore, in the conventional floor polisher having the above construction, there is a fear that the operator's fingers and like objects are sandwiched between the nuts 6 and the upper surface of the upper disk member 1 when the coil springs 7 are compressed in operation.